Sound record blank



July 18, 1933. A, MlLLER 1,919,117

SOUND RECORD BLANK Filed oct. 7, 1931 f "L ATTORNEYS 5 Patented July 18.1933

uulTsp STATES PATENT A,ol-Flou .um A. man.' or renner You soUNn nnooan nLANx appunti@ ma october v,

This invention relates to the art of recording sound. More particularly it relates to record blanks on which sound may be recorded.

I The principal object of the invention .is to provide a sound blank adapted for use in Ione of the improved methods ofrecording sound disclosed in my co-'pending a plication, Serial No. 566,152, filed Septem r 30, 1931. By the use of any of the methods disclosed in that application a sound track such as that now used in sound-on-ilm talking moving pictures` and intended for reproduction in an optical system can be produced by an initial recording of the sound on a iilm strip in a purely mechanical fashion as distinguished from an optical or photographic recording of the sound. The methods disclosed in the above mentioned application are of two general kinds, one for producing a sound track of theso-called variable-area type and the other for producing a sound track of the so-called variable-density type. The record blank to be herein described is intended for use in the method which produces the variable-densit type of sound track. For that method t e blank should have a transparent base portion and a translucent surface portion into which the 30 recording stylus may cut a sound track of the hill-and-dale type. The transparency of such a sound trackwill va in accordance with the recorded sound, it ing thegreatyest where the most translucent material has been removed from the trackb'y the recording stylus and being the least where the smallest amount of translucent material has.. been removed. The sound track thus formed is, therefore, capable of reproducing sound 4 when used in an optical reproducing system because it is capable of controlling and varyin the amount of light passing through it angl falling upon the vpl iotoe'lectric or other light sensitive cell forming a part of all op- 5 tical sound reproducing systems. ,If desired, a sound record containing av soundtrack made as above described may be used as a negative and photographic counterparts ma be made from it. 5 ne form of blank suitable for use in the iasi.v swarm 507,440.

above described method is illustrated inthe accompanying drawing. The illustrated blank is in the form of a portion of a ilexible film strip because sound-on-film talking moving pictures is now believed by me to b e Il one of t e princi al fields 0f use ofmy invention but the biiink may take the form of a disc, cylinder or the like depending upon how the sound record made `from the blank isl to be used. 0

In the drawing- .Fig 1 is an enlarged perspective view, partly in section, of a portion of a film strip so made as to constitute a record blank capable of use in the above described method il of mechanically recording sound; and

Fig. 2 represents the record'blank of Fig. 1 after a sound track has been formed thereon in accordance with my method of mechanically recordin the sound.

Referring first to ig. 1 the film stri illustrated therein has a base portion 1 w ich is trans arent and a surface portion 2 which is trans ucent. The base portion 1 ma be made of some material such as celluloi and '15 the surface portion 2 may be a coatin .of some material such as gelatin which has geen rendered translucent in any suitable way, as by solid particles held in suspension in it', by colorin or dyeing or in any other suitable way. referably'the translucent qualit is imparted. to the gelatin b some met od which will give it a grayis color. If desired, the coatin 2 may be a photographic emulsion which as been partly exposed and Il l v then developed so as to render it translucent. The translucent coating 2 should be of such a depth that it may receive a sound track of the hill-and-dale type such that for the maximum movement ofthe recording st lus the 00 groovein the translucent coatingw' l be cut V)ust about vto the celluloid base 1 or not quite to it. I have found that the translucent coating should be at least 1/2 mil in thickness and that good results have'been obtained with a .6 thickness of 1% to 2 mils. l h I The openings shown at 3' are the usual sprocket wheel openings for guiding the film stri through the sound recordi machine.

when sound is recorded on a b ank ofthe 10| 25 comprising a transparent ase havi of say cycles. 1 As stated above, the Irecord blank need notbeintheform of allmstripbutmaytake other forms, .such as a disc or linder. It is, therefore,l not tial that e hase 1 be celluloid as it might be made of some other transparent material such as glass or cellophane. Moreover the transparent portion 1 and the translucent portion 2 might he made of the same transparent material with. the surface portion of the material rendered '9 translucent to the proper depth in any suitable way.

I claim:

1. A sound record blank ada ted to receive a sound track capable of o tica reproduction a coating of translucent material consisting of a photographic emulsion which has been partly exposed and developed.-

Ving of translucent 2. A sound recordblank 'ada a sound track capable of optical reproducou, said blank comprising a llexible strip of celluloid having a coating of translucent material, said coati being of softer composition than the uloid and having a deglee of softness such that itmay be cut by a stylus, said coating havin a thickness suieient to receive a sound travi of the hill-aud-dale type.

3. A sound record blank adapted to receive a sound track capable of optical reproduction com atransparent base having a coatingu .t ueent material at least 1/2 mil in t 'ckness, said translucent material being of a softer composition thanthe mate rial of the base. .I

4. A sound record blank adapted tol receiive a sound track capable of o ical reproductionA t hav a coatmaterial substantially 171,@ to 2 mils in thickness, said translucent material being of a softer composition than Athe material of the base. Y

. JAMES A.' MILLER.`

comprising a t to receive I 

